Electric switch



Jan. 25, 1938.

E. STEWART ELECTRIC SWITCH Filed Sept. 17, 1957 3 Sheets-Sheet l Jan. 25, 1938. STEWART I 2,106,666

ELECTRIC SWITCH Filed Sept. 17, 1937 3 Sheets-Sheet 2 Jan. 25, 1938. E STEWART 2,106,666

ELECTRIC SWITCH Filed Sept. 17, 1937 5 Sheets-Sheet 5 Edi/1h $2 5272 Patented Jan. 25, 1938 UNITED STATES PATENT OFFICE 10 Claims.

This invention relates to an improved electric switch construction, and has for its principal object the provision of a novel structure which is simple in construction, economic to manufacture, and which operates in a simple and efiicient manner.

More particularly, the invention relates to that type of switch structure wherein the switch blade is moved longitudinally into or out of contact with the switch jaws, and is rotated to or from the open position. By this invention there is provided a switch structure of this type employing a novel blade supporting and operating structure comprising pivotal arms or links.

Another object of the invention, therefore, is to provide a switch structure in which there is employed a novel combination and arrangement of arms or links to support the blade and to effect the desired movement of the blade.

A further object of the invention is to provide a switch structure which employs elements that operate in a positive manner and which avoids the use of elements that are prone to stick, such as wedges, cams, etc.

Other objects and features of the invention will appear hereinafter. .In the accompanying drawmgs:

Fig. 1 is a side elevational view of the switch in closed position;

Fig. 2 is a plan view of the same;

} Fig. 3 is an enlarged plan view of the linkage mechanism;

Fig. 4 is a perspective view of the linkage mechanism! Fig. 5 is a sectional view taken along line 55 of Fig. 3;

Fig. 6 is a side elevational View of the linkage mechanism in an intermediate position during opening or closing of the switch; and

Fig. 7 is a similar view of the mechanism in the open position of the switch.

Referring to Figs. 1 and 2, there is shown the usual switch supporting structure comprising a support a stationary insulator 2 carrying the switch contacts or jaws 3, a stationary insulator 4 carrying the switch blade 5 which cooperates with jaws 3, and a rotatable insulator 6 which actuates the blade through the crank l and the link 8. The blade is connected electrically to the bar 9 by means of the flexible conductor Hi. In operation, the blade moves longitudinally until its end is fully withdrawn from the jaws 3, as shown in dot and dash outline, and then the blade is moved pivotally to open position as described hereinafter.

In accordance with the present invention, a plate H is mounted on insulator 4 and is provided with a pair of similar spaced upstanding supporting lugs 12 (see Figs. 3 and 4) and a third supporting lug l3 disposed centrally and forwardly of the lugs I2, as shown in Fig. 3. A pair of similar arms M are pivotally attached to lugs I2 at pivots |2a Whose axes are aligned one with the other. The arms l4 converge at their forward ends which are pivotally attached to a link |5'at pivot I6. The opposite end of link I5 is bifurcated and is pivotally attached to the blade at pivot ll. Intermediate their. ends, the arms M are pivotally attached to similar links 8 at pivots l9 which are axially aligned. The other ends of links l8 are pivotally attached to the blade at pivot 20. Thus the arms l4, the links l5 and I8, and the blade form a quadrilateral. Links 2| are pivotally attached to lug I3 at pivot 22, and the other ends of. these links are pivotally attached to the blade at the pivot 2 I The distance between the common axis of pivots |2a. and the common axis of pivots I9 is equal to the distance between the axes of pivots 20 and 22. The distance between the common axis of pivots l9 and the axis of pivot 20 is also equal to the distance between the axes of pivots 20 and 22. The reason for this relation will appear presently. When the switch is closed, the pivots l9 are aligned axially with pivot 22, as will be seen from Fig. 3. When the switch is in open position, the pivot 20 is aligned axially with pivots |2a, as will be seen in Fig. 7.

Assuming that the switch is closed and considering the opening operation, as the crank l is rotated, the link 8 exerts a pull longitudinally of the blade, causing the blade to move from right to left as viewed in Figs. 1 and 5. The links I5 and I8 rock about their pivots I6 and I9, and at the same time the links 2| rock about their stationary pivot 22, the arms l4 remaining in the position shown in Figs. 1 and 5. Since the pivots l9 are substantially aligned with pivot 22 at this time, and since the radial distances between these pivots and pivot 20 are equal, as above noted, the links 2| rock in unison with the links l8 about a common axis. The blade is thus moved tothe position of Fig. 6, the end of the blade being fully withdrawn from the jaws 3.

When the pivot 20 is almost or substantially aligned with pivots |2a., the blade starts to rotate about pivot 20, causing arms I 'to rotate about their stationary pivots |2a. When the pivot 20 is exactly aligned with pivots |2a, the links 2| stop moving while the blade continues to rotate about pivot 20 to the open position shown in Fig.

7. During this rotation of the blade while the pivot 2|) remains stationary, the arms l4 and links I8 rotate in unison about a common axis.

It will be seen that arms I4 and the links l5 and I8 support the blade while the links 2| serve as an additional support for the bladeand also control the movement of the blade. Essentially the pivot 20 is moved from the position shown in Fig. 5 to that of Fig. 7 and then the blade is rotated about this pivot. All the while, the arms and links cooperate to support the blade and control its movement.

The closing operation of the switch is, of course, just the reverse of the opening operation and will be clearly understood from the above description.

While it is preferred to employ the two arms hi and the two links l8 so as to provide a mechanically strong balanced structure, it will be apparent that the arms M are functionally one and the same element, as are also the links l8. The same is true of the links 2|. In some instances, it may be desired to employ a single arm or link instead of a pair of arms or links. Essentially the structure comprises a pivoted arm l4 having a stationary pivot, a pair of spaced links I5 and I8 connected between said arm and the switch blade, and another link 2! having a stationary pivot and connected to the blade pivot of one of the aforesaid links.

It will be apparent that the invention provides a switch structure comprising a novel combination and arrangement of arms and links which are positive and simple in operation. Such structure avoids the use of cams, wedges and other devices, which are prone to stick, particularly in bad weather, and sometimes become inoperative. Obviously, the accumulation of ice or other deleterious conditions cannot prevent the opera tion of the switch, for the elements employed are capable of forceful action and operation in spite of such conditions. It will be apparent that the invention is not limited to the specific structure shown but is capable of various modifications.

I claim:

1. In an electric switch, a support, an arm rotatably mounted on said support, a pair of spaced links pivotally attached to said arm, a switch blade pivotally attached to said links so as to rock said links on said arm during longitudinal movement of the blade, the blade being rotatable about a pivot of one of said links, and another link pivotally connected to said support and to said blade.

2. In an electric switch, a support, an arm rotatably mounted on said support, a pair of spaced links pivotally attached to said arm, a switch blade pivotally attached to said links so as to rock said links on said arm during longitudinal movement of the blade, the blade being rotatable about a pivot of one of said links, and another link pivotally connected to said support and to said pivot.

3. In an electric switch, a support, an arm pivotally mounted on said support, a pair of spaced links pivotally attached to said arm, a switch blade pivotally attached to said links, said links rotating about their pivots on said arm when the switch blade is moved longitudinally, and another link pivotally mounted on said support and pivotally attached to said blade so as to rotate about its pivotal mounting during the longitudinal movement of said blade, the blade being rotatable about the pivot connection of said other link when in retracted position while said arm rotates about its mounting pivot.

4. In an electric switch, a support, an arm pivotally mounted on said support, a switch blade, a pivot on said blade, a link pivotally attached to said arm and to said blade pivot, a stationary pivot mounted on said support, a link P Y attached to said blade pivot and to said stationary pivot, and another link pivotally attached to said arm and to said blade.

5. In an electric switch, a support, an arm pivotally mounted on said support, a pair of spaced links pivotally attached to said arm, a switch blade pivotally attached to said links, the link nearest the mounting pivot of said arm being equal in radial length to the distance of its pivot on said arm from said mounting pivot, said links rotating about their pivots on said arm when the switch blade is moved longitudinally, and another link pivotally mounted on said support and pivotally attached to said blade at the pivot of the said link nearest the arm mounting pivot, said other link being equal in length to the said distance whereby to rotate about its pivotal mounting in unison with the said link nearest the arm mounting pivot during the longitudinal movement of said blade, the blade being rotatable about the pivot connection of said other link when in retracted position while said arm rotates about its mounting pivot.

6. In an electric switch, a support, a stationary pivot mounted on said support, an arm rotatably mounted on said pivot, a pivot on said arm, a switch blade, a pivot on said blade, a link connected between said arm pivot and said blade pivot, the distance between the axis of said stationary pivot and the axis of said arm pivot being equal to the distance between the axis of said arm pivot and the axis of said blade pivot, a second stationary pivot mounted on said support, a second link connected between said second stationary pivot and said blade pivot, the distance between the axis of said second stationary pivot and said blade pivot being equal to the aforesaid distances, and a third link pivotally connected between said arm and said blade.

'7. In an electric switch, a support, a pair of spaced axially aligned pivots on said support, a switch blade, a pivot on said blade, a pair of arms rotatably mounted on said support pivots, a pair of axially aligned pivots one on each of said arms, a pair of links connected respectively between said arm pivots and said blade pivot, another pivot on said support, another link connected between said other support pivot and said blade pivot, and another link pivotally connected between the ends of said arms and said blade.

8. In an electric switch, a support, an arm pivotally mounted on said support, a switch blade, a pair of spaced links pivotally connected between said arm and said blade, and forming with the arm and the blade a quadrilateral, and means arranged cooperatively with said arm and said linkst to support the blade and control its movemen 9. In an electric switch, a support, an arm pivotally mounted on said support, a switch blade, a pair of spaced links pivotally connected between said arm and said blade, and forming with the arm and the blade a quadrilateral, and another link pivotally connected between said support and said blade.

10. In an electric switch, a support, an arm pivotally mounted on said support, a switch blade, a pair of spaced links pivotally connected between said arm and said blade, and forming with the arm and the blade a quadrilateral, and another link pivotally connected between said sup- $0125 and the blade pivot of one of the aforesaid EDWIN STEWART. 

